Abstract
In concentrations from 1 to 100 μg/ml., amphetamine potentiated responses of the isolated vas deferens preparation of the guinea-pig stimulated via the hypogastric nerve at rates of from 5 to 40 shocks/sec. Potentiation was more pronounced with low than with high stimulus frequencies. A concentration of 500 μg/ml. of amphetamine had a blocking action which was more pronounced at high than at low stimulus frequencies. This effect contrasted with the ganglionic blocking action of hexamethonium which had a greater effect at low than at high stimulus frequencies.